Thanks @SiliconWizard
Your suggestion solved the initial error but now I'm getting this:
microcap 12 failed to converge during ac function source iterations
During a transient DC operating point, or the operating point calculation prior to an AC analysis, or during a DC analysis, if the number of iterations required to solve the network equations exceed the specified maximum, this message is issued.
I also tried in LTspice and initially got the diode issue, applied your suggestion and then got this:
ERROR: Node U1:11 is floating and connected to current source G:U1:U2:R1
ERROR: Node U1:U_TF:VP1 is floating and connected to current source G:U1:U_TF:P1
ERROR: Node U1:U_TF:VP2 is floating and connected to current source G:U1:U_TF:P2
ERROR: Node U1:U_TF:VP3 is floating and connected to current source G:U1:U_TF:P3
ERROR: Node U1:U_TF:VP4 is floating and connected to current source G:U1:U_TF:P4
ERROR: Node U1:U_TF:VZ1 is floating and connected to current source G:U1:U_TF:Z1
ERROR: Node U1:U_TF:VZ2 is floating and connected to current source G:U1:U_TF:Z2
ERROR: Node U1:U_TF:VZ3 is floating and connected to current source G:U1:U_TF:Z3
ERROR: Node U1:U_TF:VZ4 is floating and connected to current source G:U1:U_TF:Z4
ERROR: Node U1:17 is floating and connected to current source G:U1:U_TF:Z5
Direct Newton iteration failed to find .op point. (Use ".option noopiter" to skip.)
Starting Gmin stepping
Increasing initial diagonal Gmin to 100
Test circuit as per TI's application note (single LM3886 in non-inverting config.)